Hearn Iron Works Coehorn Mortar

[keithinvestigations]

Who here has one?  I just ordered mine and am anxiously awaiting for it. 

[KABAR2]

I don't have one but have seen one up close some time back,

if memory serves the only detractors are for it's size the bore is on the small side

& it is bored straight with no chamber.....if I had one I would be adding a chamber to it.....

[keithinvestigations]

They are now making a 3" bore size.  Help me out understanding how a powder chamber would be helpful.  Thanks.

[Cat Whisperer]

By reducing the diameter and keeping the outside diameter the same one increases the wall thickness.

A powder chamber allows VERY thick walls around the powder (when it burns there will be a pressure spike) after the spike the pressure is MUCH lower which the walls of the tube can easily handle.  That allows for a more powerful and lighter tube.

[keithinvestigations]

ok, thanks. 

[LeeBo]

My bother and I have a Hern Iron Works Coehorn 2 1/4" bore. We use 80 grains of 1F Schuetzen powder and can throw a billiard ball about 95 yards. My back yard lawn is only about 130 yards than a 1/2 mile of woods. Hard to find a 2 1/4 ball in the woods.We have shot a few Racquetballs but being rubber they disappeared into the wild blue yonder or the Hundred Acre Wood. I don't think a powder chamber would make a difference or is necessary. I feel safe using the Hern mortar. Lee

[dan610324]

hi Lee
welcome to the board

you must remember that cast iron is a hard but fragile material
so if there ever will be an accident it will spread shrapnell all over the place

if you got a 2.25" bore , whats the outer diameter surrounding the chamber area ??

[Cat Whisperer]

LeeBo  --

WELCOME tothe board!

We'd love to see some pictures of smoke and flame!

[little seacoast]

 Hi Dan, The Hern barrel is cast around a proper steel liner with a welded plug. There is 2.25" of barrel on each side of the bore.  They do not have a powder chamber and function well without one. I have talked with them extensively regarding the powder chamber issue (or non issue) in their mortars and howitzers- they feel that they cannot do this due to cost constraints.  Having used mine extensively with zinc, lead, and can projectiles I'll have to say it doesn't seem necessary in these reduced bore sizes.

[dan610324]

that sounds good to me , but isnt it difficult to ignite small charges and have a consistent length in several shots without a chamber ??

[little seacoast]

So far no problems with consistency. Powder is premeasured into small containers  and placed in the bottom of the bore by pouring  with a funnel and tube arrangement, fuse is inserted next, then projectile.  I'd have loved to have a chamber but it just isn't an available option.

[Lee1966]

Dose there mortar have a barrel liner in it?

I have there ENGLISH SWIVEL GUN, 1750-1815 mounted on a Canadian Cannon Company Inc. Navy Carriage kit.

My cannon barrel's liner is off just a smig, Shoots a little to the right.